This invention relates to protection of circuit identification information and more particularly, to an arrangement for protecting a serial number of a printed circuit board.
A problem for companies who manufacture, sell, and service large electronic systems is to be able to identify on a customer site or at a repair facility individual printed circuit cards. Within the telecommunication industry, the cost of an individual printed circuit board is thousands of dollars. In addition, because of the global economy, a manufacturer may choose to sell the identical printed circuit board at a lower cost, in a first country than in a second country. The so-called gray market is the practice of taking cards that are sold in the first country and shipping them to the second country. From a contractual point of view, this practice is not allowed, however it is difficult to prevent unless individual cards can be identified with a unique serial number.
The second problem that manufacturers have with the more expensive and more complex cards is the necessity of being able to track individual cards for repair purposes. For example, most large system manufacturers maintain a data base that identifies each-card produced by that manufacturer by a unique serial number. This serial number is utilized to identify problems that have been occurring on the printed circuit board and also to be able to know what vintage a particular type of printed circuit board is. Finally, manufacturers also offer service contracts for the maintenance of their systems. A large customer may choose to have a maintenance contract on one system but not on another system. The problem that occurs is that if the customer detects that a printed circuit board has, failed in a system that does not have a maintenance contract, the customer may move the failed printed circuit board to the system that has the maintenance contract. Hence, even within a single country, it is necessary to be able to identify an individual printed circuit board to an individual system.
The prior art has attempted to address these problems in a variety of ways. First, is to place the serial number of the card in printable form on the printed circuit board using a barcode or a human readable number. The problem with this solution is that individuals simply manufacture their own labels. Manufacturers have also attempted to mold or laser reproduce serial numbers into the face plates of printed circuit boards or on the printed circuit boards themselves. These techniques suffer from cost and also in the case of the face plates individuals simply remove the face plates and move it to another printed circuit board. A final solution is to utilize unique integrated circuits that have a preset number. Such an integrated circuit is placed on the printed circuit board in a manner in which it can be read externally by a device. The problem with this solution is that these devices are easily identified on a printed circuit board and can be removed and placed on another printed circuit board. In addition, the number is determined by the manufacturer of the integrated circuit and does not directly correspond With the actual serial number of the printed circuit board. In addition, there is the cost associated with the purchase and the installation of a unique integrated circuit on a printed circuit board for the sole purpose of identifying the board. One such device that has a pre-programmed identification number is the DS1990A manufactured by Dallas Semiconductor.
The foregoing problems are solved and a technical advance is achieved by allowing a test set during the final testing of a printed circuit board to insert the actual serial number of the printed circuit board into one or more, memory devices on the printed circuit board. Advantageously, the test set obtains the serial number of the printed circuit board by the utilization of scanner which scans the serial number from the barcode on the printed circuit board. Further, the barcode""s serial number is uniquely identified by the manufacturer in the manufacturer""s database. The test set inserts the serial information into one or more memory devices on the printed circuit board. Advantageously, the serial information is encrypted before being inserted into the memory devices. The serial number is then transmitted to the manufacturer""s database where it is stored and associated with the telecommunication switching system that the printed circuit board will be inserted into. The central database in response to the serial information transmits operational information such as programs and data to the test set for insertion into the printed circuit board. After the printed circuit board has finished being tested on the test set, it is made operational in its assigned telecommunications switching system either at the manufacturer""s location or in a field installation. During routine maintenance, a processor controlling the telecommunication switching system requests the serial number from the printed circuit board. A controller providing control of the printed circuit board decrypts the serial number and transmits it to the processor. The processor then transmits a request to the manufacturer""s database to verify that the printed circuit board as identified by the serial number should be operational in this particular telecommunication switching system. This request can be made either by a direct telecommunication call or via the Internet. The manufacturer""s database determines if the printed circuit board should or should not be operational in this particular telecommunication switching system. If the answer is yes, the card is allowed to remain operational. If the answer is no, the processor controlling the telecommunication switching system disables the printed circuit board and initiate a maintenance alarm. Advantageously, the checking to verify that the printed circuit board is operational in its assigned telecommunication switching system prevents the unauthorized use of the printed circuit board in other telecommunication switching systems.
These and other features and advantages of the invention will become apparent from the following description of the illustrative embodiments of the invention considered together with the drawing.